SpurGuard™ is a device-port, short circuit protection technique

that minimizes susceptibility to single points of failure. The F300

Megablock has built-in SpurGuard™ protectors that prevent a short

circuit in any of the individual field devices or spur cable runs, from

bringing down the entire fieldbus segment. A red LED near each

spur connection indicates when a spur is shorted and hence in “over

current” mode.

The optional FS32 modules can provide surge protection for the

F300 products on both the trunk and spur terminals. These pluggable

modules are simple to fit in a new installation, or as a retrofit option.

A range of MTL Process Junction Boxes in stainless steel and carbon

loaded, glass-reinforced polyester are available for mounting Megablock

wiring components. They offer plenty of space for termination and

wiring, making it easy to install and maintain the fieldbus system.

The black Trunk In/Out pluggable connector allows replacement of

a Megablock without breaking the trunk connection to other devices

on the fieldbus segment. The F97 terminator supplied should be

mounted in the Trunk-out connection to provide termination when the

Megablock is located at the end of the fieldbus segment; alternatively,

if the segment is extended, it can be removed to ensure the correct

termination is maintained.

Spur connections to the Megablock are made using pluggable, grey,

screw-terminal or spring clamp terminal connectors. Wire terminations

can be made to the individual connectors before plugging them into

the Megablock. Devices can then be connected and disconnected

easily during commissioning. After commissioning, retaining screws

are tightened to secure each connector to the Megablock. Separate

numbered connections are provided for each spur drop.

Passive hubs for general purpose, zone 2 & division 2 fieldbus networks

• Single-piece Trunk In/Trunk Out connector simplifies installation and maintenance

• Pluggable trunk and spur surge protection option

• Choice of rising cage clamp screw or spring clamp terminals

• Locate Megablock in Zone 2 or Division 2

• Connect to Ex nA, Ex ic or non-incendive devices in Zone 2/Division 2

• Connect to Ex d, explosionproof devices in Zone 1/Division 1

F300 Megablocks are DIN-rail mounted passive hubs for Foundation™

fieldbus H1 and Profibus PA networks for general purpose, Zone 2 and

Division 2 applications. They provide a simple means of connecting field

devices to the network trunk cable, and protect the segment from spur

short circuits. Megablocks minimize hand wiring and allow individual

devices to be added to and removed from the segment without

disrupting network communication. A green power LED on each unit

indicates whether at least 10V dc is present. F300 Megablocks are

available in four, eight, and twelve drop versions.

MECHANICAL

Enclosures

An enclosure is required to house and protect the Megablock device coupler and the

F30 Ex ic adaptor for field operation. The type of enclosure must be chosen to suit

both the hazardous atmosphere likely to be encountered and the general conditions

appropriate to its environmental exposure. For installation in hazardous areas, the

enclosure must meet the requirements of a recognised method of protection

according to IEC 60079-0. clause 1.  In addition, the following conditions should

always be considered to ensure safe and reliable operation.

a) Prevent any form of pollution that could compromise the operation.

b) Provide an adequate level of mechanical protection. This can be achieved

by selecting a protected location, a suitable enclosure, or a combination of

both.

c) Ensure that all cable entries and connections are secure by making

provision for the careful routing and securing of all cables.

d)Provide adequate security against unauthorized interference.

e) Conform to the permitted ambient operating temperature range of  –40°C to +70°C.

The F30 adaptor

The F30 adaptor is connected in series with the trunk wiring to the Megablock (see

Figure 2.1) and limits the voltage to ensure that the ‘Uo’ at the Megablock spurs is

less than the 17.5V value required for compatibility with FISCO-certified instruments.

Where the voltage arriving at the F30 is higher than this (for example, if the trunk

cable is only short in length resulting in only a small voltage drop in the cable), the

F30 regulates the voltage to less than 17.5V.  Final current limiting for each spur is

provided by the short-circuit limiting circuits built in to the F300 Megablock, for which

Ex ic approval already exists. As a result, the combination of F30 and F300 meets the

requirements for Ex ic voltage and current limitation.

The F30 is designed for use only with MTL F304. F308 and F312 Megablock types,

typically providing up to twelve Ex ic spurs per fieldbus segment.  These spurs

may be all from one F312 Megablock in one enclosure, or distributed between two

separate enclosures – see Section 4.7.

The spurs are compatible with FISCO and Entity certified fieldbus instruments, and

where FISCO instruments are selected, cable parameter calculations are not required.

Power supplies

For Ex ic spur applications, the F30 and associated Megablock must be supplied by

9192-FP power supply modules in simplex or redundant configuration. The 9192

FP module has the necessary voltage limiting and is designed to fit on one of the

backplanes from the 918x-x2 range of fieldbus power supply systems, all of which

are capable of providing n+1 redundancy for maximum availability.

The 918x family of redundant power supplies contains a range of solutions to suit

different host interfaces, consult Eaton for the model appropriate to the host and

install the chosen model in accordance with the instructions provided with it.

DESCRIPTION

The Ex ic concept

In May 2013 the Ex nL certification method was removed from the IEC60079-15

standard, and replaced by intrinsic safety method Ex ic in IEC60079-11.  Although Ex

ic and Ex nL are broadly similar, Ex ic brings with it additional requirements that are

associated with the wider intrinsic safety approach.

Ex ic is a new level of protection under the intrinsic safety protection method,

suitable for use in Zone 2 only, where Ex ic circuits may be ‘live-worked’ in the

presence of a flammable atmosphere.  It follows the same energy-limitation principles

as all intrinsically safe circuits, but safety is maintained only in ‘normal operation’.

Host H1 control system

In a typical network installation using the F30 Ex ic Adaptor, F300 Megablock and

9192-FP power supply module, the H1 interface of the host control system is

electrically connected in parallel with the fieldbus trunk circuit. The H1 interface

and host control system are not required to carry hazardous area certification in

this application, but they must comply with electrical safety standards IEC61010 or

IEC60950.  Apparatus carrying a CE mark will comply with this requirement. This

requirement also applies to any other apparatus that is connected electrically in

parallel with the fieldbus trunk circuit.v

OVERVIEW

This manual explains the installation and maintenance procedures for the F30 Ex ic

Adaptor and should be read in conjunction with the product datasheet that contains

the electrical data.

The F30 Ex ic Adaptor is an accessory that works with MTL F300 range of DIN-rail

mounted, passive device couplers and extends their usage by enabling them to

provide Ex ic spur connections in Zone 2 hazardous areas. The F300 device couplers

provide a simple means of connecting a group of local field devices to the network

trunk cable that carries the signal and provides the necessary power supply.

This manual also introduces the concept of the Ex ic intrinsic safety method of

protection and explains how it applies to the F300 device couplers and the F30 Ex ic

adaptor.  Other topics will include the trunk power supply and suggested enclosures

for housing the adaptor and hubs in the hazardous area.

NOTE

The user/installer should also refer to the following datasheets and installation manuals:

• F300 range of Megablocks data sheet, EPS F300

• F300 range of Megablocks installation manual, INM F300

• 918x  Redundant Power Supply data sheets, EPS 918x

• Redundant Power Supply installation manuals, INM 918x in order to obtain

details of their installation, operating parameters and usage.

Overview

Certifications and compliances

• For a complete listing of certification and approvals across our MTL Megablock range,

download the product datasheets in the resources section of this family page.

Design features

• A green power LED on each unit indicates whether at least 9V dc is present.

• Available in two, four, eight, ten and twelve drop versions

• Multiple Megablocks are easily wired to one another to allow larger segments to be

constructed

• Choice of rising cage-clamp screw terminal or spring clamp type connections simplifies

commissioning and maintenance

• Available with built-in SpurGuard™ protectors that prevent a short circuit in any of the

individual transmitters or spur

cable runs from bringing the entire fieldbus segment down

• A red LED near each spur connection indicates that a spur is shorted and is in

“over-current” mode

Standard materials

• Housing:  Polycarbonate

CERTIFICATION

MTL7000 Series barriers protect devices located in all normally

occurring explosive atmospheres, including air/flammable gas

mixtures, dusts and fibres.  MTL7000 Series barriers are certified [EEx

ia] IIC (except MTL7129P+, certified IIB) BY BASEEFA to CENELEC

standards, by FM in the USA, CSA in Canada and also by other

authorities, providing worldwide certification. MTL7000 Series

barriers are designed to the same safety descriptions as MTL700

Series equivalents (in some cases slightly stricter) and can therefore be

used for the same applications.

HOW THEY WORK

All MTL7000 Series barriers are based on the same simple principle.

Each channel contains three stages of Zener or forward-connected

diodes and an ‘infallible’ terminating resistor. In the event of an

electrical fault in the safe area, the diodes limit the voltage that can

reach the hazardous area and the resistor limits the current: active

output-current limiting circuits are not used. An internal fuse protects

the diodes, and the three stages of voltage limitation ensure continued

safety if the first or second stage should fail. MTL7100 barriers have

an additional replaceable fuse which protects the internal fuse.

The MTL7000 Series includes seven key barrier types which cover the

majority of applications, simplifying barrier selection and the

maintenance of spares stocks.